rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=1994/1/0x4000000000000000 softirq=84978/84982 fqs=0
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P17526/1:b..l
rcu: (detected by 1, t=10505 jiffies, g=71201, q=191 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 17523 Comm: syz.9.2968 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0x10/0x18
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 52 b8 01 00 00 00 31 d2 f0 0f b0 17 <75> 06 5a c3 cc cc cc cc 56 0f b6 f0 e8 9f ff ff ff 5e 5a e9 98 3e
RSP: 0000:ffffc90005027778 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffff8880b8627a80 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffff8880b8627a80
RBP: 1ffff110170c4f51 R08: ffff8880b8627a83 R09: 1ffff110170c4f50
R10: dffffc0000000000 R11: ffffed10170c4f51 R12: dffffc0000000000
R13: 1ffff110170c4f52 R14: ffff8880b8627a90 R15: ffff8880b8627a88
FS: 00007fdc000106c0(0000) GS:ffff888125c11000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f05b41d4f58 CR3: 000000006587c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000082
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:562 [inline]
queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline]
do_raw_spin_unlock+0x122/0x240 kernel/locking/spinlock_debug.c:142
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline]
_raw_spin_unlock_irqrestore+0x78/0x110 kernel/locking/spinlock.c:194
unlock_hrtimer_base kernel/time/hrtimer.c:1020 [inline]
hrtimer_try_to_cancel+0x3be/0x420 kernel/time/hrtimer.c:1367
hrtimer_cancel+0x3b/0x50 kernel/time/hrtimer.c:1488
perf_swevent_cancel_hrtimer kernel/events/core.c:11817 [inline]
cpu_clock_event_stop+0xd9/0x130 kernel/events/core.c:11867
__perf_event_overflow+0x580/0xe40 kernel/events/core.c:10333
perf_swevent_hrtimer+0x3c5/0x550 kernel/events/core.c:11773
__run_hrtimer kernel/time/hrtimer.c:1761 [inline]
__hrtimer_run_queues+0x4dd/0xc60 kernel/time/hrtimer.c:1825
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
__sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0033:0x7fdbff18eec9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fdc000100e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007fdbff3e5fa8 RCX: 00007fdbff18eec9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fdbff3e5fa8
RBP: 00007fdbff3e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdbff3e6038 R14: 00007ffd80ca2270 R15: 00007ffd80ca2358
task:syz.1.2967 state:R running task stack:26920 pid:17526 tgid:17526 ppid:12443 task_flags:0x400040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7145
preempt_schedule+0xae/0xc0 kernel/sched/core.c:7169
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
do_anonymous_page mm/memory.c:5111 [inline]
do_pte_missing mm/memory.c:4232 [inline]
handle_pte_fault mm/memory.c:6052 [inline]
__handle_mm_fault+0x3a6c/0x5440 mm/memory.c:6195
handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364
do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f05b3e4d9ef
RSP: 002b:00007ffccef12e68 EFLAGS: 00010206
RAX: 000000008479a5eb RBX: 00007f05b4d15720 RCX: 0000000000000020
RDX: 00000000000005eb RSI: ffffffff8479a5eb RDI: 0000000000000000
RBP: ffffffff8479a5eb R08: 00007f05b41d0000 R09: 00007f05b41d2000
R10: 000000008479a5ef R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffffffff8479a3cd R15: 0000000000000020
rcu: rcu_preempt kthread starved for 10505 jiffies! g71201 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:26008 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 3586 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xd3c/0x12d0 kernel/smp.c:877
Code: 01 31 ff e8 b6 63 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 61 5f 0b 00 eb 38 f3 90 42 0f b6 04 2b 84 c0 75 11 <41> f7 04 24 01 00 00 00 74 1e e8 45 5f 0b 00 eb e4 44 89 e1 80 e1
RSP: 0018:ffffc9000c457660 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 1ffff110170c8341 RCX: ffff8880313b8000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000c4577e0 R08: ffffffff8fa3b537 R09: 1ffffffff1f476a6
R10: dffffc0000000000 R11: fffffbfff1f476a7 R12: ffff8880b8641a08
R13: dffffc0000000000 R14: ffff8880b873b1c0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125d11000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2a864e CR3: 000000000df36000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000200000000300
DR3: 0000200000000300 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044
on_each_cpu include/linux/smp.h:71 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2653 [inline]
smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2863
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245